Changes in temperature may impact stroke risk, hospitalization, and even death from stroke, new research says.

Major changes in temperature and humidity could be linked to more hospitalizations from stroke, researchers say. In their study, which was presented at the American Stroke Association’s International Stroke Conference in San Diego, the researchers also found that colder temperatures were linked to more hospital stroke deaths. With every 1°F increase in temperature, there was a 0.86% decrease in likelihood of being admitted to a hospital for a stroke, and a 1.1% decrease in dying from a stroke.

To come up with these findings, the researchers look at more than 134,500 people sent to hospitals between 2009 and 2010 for a stroke. They then compared the stroke cases and outcomes to temperature data for that time period.

The mechanics behind the trend are not fully understood, but in an interview with the Associated Press, researchers said that our blood vessels constrict in cold weather and this can raise blood pressure and add stress to the body, which makes blood more likely to clot. High humidity can also cause dehydration, which leads to an increased risk for clotting and stress.

More research is needed to confirm the findings, but the researchers say that the people at risk for stroke may want to protect themselves from exposure to massive changes in temperature and humidity.